Heartworm Basics: Disease, Prevention, Treatment
By Heather Duncan, D.V.M.
Heartworms are parasites that are carried by mosquitoes. In South Carolina, we see a significant heartworm population due to our increased mosquito problem which is a year round concern. Transmission occurs when mosquitoes bite an infected animal and then bite a dog. At that point they inject heartworms through their bite wounds. Around six months later these larva migrate into the vessels of the lung and heart as adult worms. Since the dog is the primary host, adult heartworms can live up to 5-7 years. Cats are not the primary host but can still be infected. These worms typically live between two to three years. Heartworms can grow to around 12 inches long and can lead to heart failure, significant lung disease and organ damage because they circulate in the bloodstream; therefore, our best defense is prevention.
Prevention is easy and there are multiple options. River Oaks Animal Hospital does require an annual heartworm test in dogs because treatment is best done in the early course of disease and while our preventives are highly effective there is nothing that is 100% effective. If a dose is accidentally forgotten or given late, we are able to diagnose early and then start treatment before any permanent damage to the lungs and heart. There is treatment for dogs but unfortunately there is no treatment for cats. Heartworm treatment is expensive and time-consuming. It’s tiresome for both the pet and owner because it requires a significant time investment. Dogs undergoing treatment need their activity restricted for the entire treatment course. The treatment is a series of 3 injections given over a time period of two months. It is a significant time investment and monetary investment so our best defense is to prevent it from happening. Cats are a little different. They do not grow and reproduce heartworms like dogs do since they are not the primary host . They generally only have one to three heartworms. We do not routinely test cats because annual testing is not straightforward. There are no treatment options available in cats which is why prevention is so important.
The good news is that there are multiple prevention products available. In dogs, we have a monthly chewable that prevents heartworms, fleas, ticks, and intestinal parasites. We also have a great option called ProHeart 12. It is a simple injection given under the skin during a routine wellness examination. ProHeart 12 is the perfect option for the owner who has trouble remembering to give their dog a heartworm chewable each month and ensures that their pet is completely covered for 12 months. For cats, we have a monthly topical product that is applied to the back of the neck directly on the skin and prevents fleas and heartworms.
There is an option for everyone that works for everyone. If you have any questions next time you’re in the office please ask one of our team members. You can also give us a call at (843) 236-6080. Please click on the link below to see our YouTube video about Heartworms Basics.